左旋多巴对弱视眼视诱发电位影响的研究

目的:探讨左旋多巴治疗弱视的效果。方法:正常眼和弱视眼服用单次剂量左旋多巴前后进行图形视诱发电位(pattem visual evoked poten-tial,PVEP)检测。结果:正常眼服药后中空间频率PVEP的N_1P_1振幅和高空间频率PVEP的P_1N_2振幅增大,弱视眼服药后低空间频率PVEP的N_1波潜伏期和中空间频率PVEP的P_1波潜伏期缩短。结论:左旋多巴可改善弱视眼的视功能,可作为弱视的一种新的治疗方法。眼科学报1997;13:182—185。     

用小波变换提取视觉诱发电位信号

视觉诱发电位（ＶＥＰ）信号的动态提取及处理具有重要的临床意义。通过硬件采集的ＶＥＰ信号经过叠加平均处理后仍含有大量背景噪声，不能直接用于诊断分析。小波变换是一种新兴时频分析方法，适于分析非平稳信号。在我们研制的视觉生理地形图系统中，成功地用它从背景噪声中提取出ＶＥＰ信号，完成信号的预处理。     

Generators of visual evoked potentials for faces and eyes in the human brain as determined by dipole localization

Human visual evoked potentials were recorded during presentation of photos of human and animal faces and various face features. Negative waves with approximate peak latencies of 165 msec (N170) were bilaterally recorded from the occipito-temporal regions. Mean peak latencies of the N170 were shorter for faces than eyes only. Analyses of amplitudes of evoked potentials indicated that the N170 elicited by faces reflected activity of a specific neural system which was insensitive to detailed differences among individual faces regardless of species, and consequently suggest that this system might function to detect existence of faces in general. On the other hand, the mean amplitude of the N170 elicited by human eyes was significantly larger than those by animal eyes. These differences in response latencies and amplitudes of the N170 suggest existence of at least 2 different visual evoked potentials with similar latencies (i.e., N170) which are sensitive to faces in general and human eyes, respectively. Dipole source localization analysis indicated that dipoles for the N170 elicited by eyes were located in the posterior inferior temporal gyrus, and those for faces, located initially in the same region, but moved toward the fusiform and lingual gyri at the late phase of the N170. The results indicated that information processing of faces and eyes separated at least as early as the latency of the N170 at the posterior inferior temporal gyrus as well as the fusiform and lingual gyri, and might provide neurophysiological and anatomical bases to an initial structural encoding stage of human faces.     

癌瘤患者骨髓细胞c－erbB和c－erbA的基因异常

本文在大系列研究造血系统恶性肿瘤-白血病和白血病前期的基础上，对３１例恶性肿瘤患者骨髓进行血液学、细胞和分子遗传学研究。发现恶性肿瘤患者骨髓有与白血病前期骨髓相似的病态造血（Ｍｙｅｌｏｄｙｓｐｌａｓｉａ）和相关基因异常即ｃ－ｅｒｂＢ基因重排、扩增和ｃ－ｅｒｂＡ缺失。它们不仅同骨髓红系病态造血相关，也同巨核系病态造血相关。骨髓巨核系病态造血及其相关基因异常可能代表急性淋巴细胞白血病等多种恶性肿瘤的早期病变。而ｃ－ｅｒｂＢ重排及其相关的骨髓巨核系异常增生可能是肿瘤发病的遗传背景。     

急性甲醇中毒患者的VEP分析

目的探讨急性甲醇中毒患者的视觉诱发电位（VEP）波形的异常变化及其与血甲醇浓度的相关性。方法对26例（52眼）甲醇中毒患者进行VEP检查及血甲醇浓度的测定。结果病程第一阶段共观察26人（52眼）,其中未引出VEP波形的有29只眼,波幅减低的有20只眼,波形P100潜伏期延长的有7只眼;病程第二阶段共观察17人（34眼）,其中未引出VEP波形的有10只眼,波幅减低的有22只眼,波形P100潜伏期延长的有11只眼;病程第三阶段共观察9人（18眼）,其中未引出VEP波形的有7只眼,波幅减低的有8只眼,波形P100潜伏期延长的有4只眼。未见血甲醇浓度与双眼P100潜伏期均值之间有明显相关性（P〉0.05）。结论VEP检查可以对甲醇中毒患者视神经功能损害提供可靠的诊断依据。急性甲醇中毒引起的视神经损害相对于异常甲醇浓度的降低以及其他临床症状消失具有滞后性与持续性。     

重症肌无力20例患者VEP、SEP、BAEP的变化及临床意义

目的:比较重症肌无力(MG)患者模式翻转视觉诱发电位(VEP)、体感诱发电位(SEP) 及脑干听觉诱发电位(BAEP)3种诱发电位的变化。方法:测定20例新诊断的MG患者和50例正常人的VEP、SEP及BAEP。结果:与正常人比较,VEP 6例(30％)异常,其中5例双侧和1例单侧P100潜伏期延长,波幅降低;SEP 4例(20％)异常,其中3例双侧和1例单侧N13-N20波间期延长,波幅降低; BAEP 9例(45％)异常,其中7例双侧和2例单侧的Ⅲ-Ⅴ和Ⅰ-Ⅴ波间期延长,Ⅲ、Ⅴ波波幅减低。结论:有部分MG患者的VEP、SEP及BAEP有明显的变化,提示他们可能存在中枢神经系统胆碱能通路不同程度受损害,并且这三种诱发电位可能对胆碱能传递受损程度的判断有临床价值。     

Hemi-field pattern visual evoked potentials: A comparison of display and analysis techniques

Summary Three methods for analyzing the spatial organization of visual evoked potentials were compared. Pattern reversal visual evoked potentials were obtained from a single subject under three viewing conditions: stimulation of the left, right, and both visual fields. The scalp distribution of the VEP to 1 deg checks was displayed using three recording and analysis techniques: a conventional horizontal occipital array of electrodes, topographic mapping, and 3-dimensional evoked potentials. All three techniques revealed "paradoxical" lateralization of P100. The relative merits of each technique are discussed.We are grateful to Susan Hoffmann-Nader and Rebecca Clark-Bash for data collection. This research was supported in part by the Brain Research Foundation of the University of Chicago.     

The human motion onset VEP as a function of stimulation area for foveal and peripheral vision

We studied amplitude of the wave N200 of the motion-onset VEP by varying the side length of a square stimulation field between 0.5 and 7 degrees. A significant increase in amplitude was obtained between 0.5 and 1 degree of side length in central stimulation and between 0.5 and 5 degrees in 10-degree peripheral stimulation. Variations of spatial frequency between 0.34 and 6.8 c/deg did not modify the amplitude size, ie, no tuning effect could be found. The results of simultaneous and separate stimulation of foveal and parafoveal regions support the observation that the stimulation field size is a minor influence. Features of motion-sensitive cortical neurons, such as those found in monkeys, could account for this behavior.     

A new approach to the study of ocular chromatic aberrations

We measured the ocular wavefront aberration at six different visible wavelengths (between 450 and 650 nm) in three subjects, using a spatially resolved refractometer. In this technique, the angular deviation of light rays entering the pupil at different locations is measured with respect to a target viewed through a centered pupil. Fits of the data at each wavelength to Zernike polynomials were used to estimate the change of defocus with wavelength (longitudinal chromatic aberration, LCA) and the wavelength-dependence of the ocular aberrations. Measured LCA was in good agreement with the literature. In most cases the wavefront aberration increased slightly with wavelength. The angular deviations from the reference stimulus measured using a magenta filter allowed us to estimate the achromatic axis and both optical and perceived transverse chromatic aberration (TCA), (including the effect of aberrations and Stiles-Crawford effect). The amount of TCA varied markedly across subjects, and between eyes of the same subject. Finally, we used the results from these experiments to compute the image quality of the eye in polychromatic light.